Method for preparing chromic oxide

A production method and technology for chromium oxide, applied in the direction of chromium oxide/hydrate, etc., can solve the problem of not involving and considering chromate and dichromate, and achieve the effects of low price, cost reduction and energy consumption

Inactive Publication Date: 2011-04-13
TIANJIN PAISEN TECH
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Problems solved by technology

[0010] Chinese patent ZL01141529.0, ZL01136315.0, ZL02153523.X, ZL02153523.X, patent application publication CN100999335A (2006) etc., these methods are all with chromate and dichromate as raw material, or acidify or not acidify, adopt sugar Chromium oxide, alcohols, aldehydes, hydrazines, organic acids and other low molecular weight organic substances, or ferrous sulfate, sodium sulfide, ammonium salts as reducing agents, supplemented by different additives for acid reduction or hydrothermal reduction to obtain chromium oxide products, these research methods do not involve and

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  • Method for preparing chromic oxide

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Embodiment 1

[0047] Please refer to figure 1 As shown, the method of the present embodiment includes: preparing 1000ml of sodium chromate solution with a concentration of 1.85mol / l to become the initial reaction liquid, placing it in a 3000ml reactor, and filling it with a hydrogen pressure of 3.1MP (about 100% of the theoretical hydrogen distribution amount) . Control the heating voltage of 180v and the stirring speed of 450rpm to make the reaction system heat up and react. The maximum pressure of the system was 16.5MP, and the reaction was carried out at 350°C for 120 minutes to obtain a complete reaction solution, which was then naturally cooled to room temperature and discharged. The conversion rate of chromium in the reaction solution was detected by the method described in GB / T 1611-2003, and the conversion rate of chromium was 81.58% (calculated hydrogen utilization rate was 81.58%). The product was separated from solid and liquid, and the solid was hydrated chromium oxide. The ca...

Embodiment 2

[0049] Prepare 1000ml of sodium chromate solution with a concentration of 2.47mol / l as the initial reaction solution, place it in a 3000ml reactor, and fill it with a hydrogen pressure of 4.9MP (about 119% of the theoretical hydrogen distribution). Control the heating voltage of 180v and the stirring speed of 500rpm to make the reaction system heat up and react. The maximum pressure of the system is 12.0MP, and the reaction is carried out at 300°C for 120 minutes to obtain a complete reaction solution, which is then naturally cooled to room temperature and discharged. The conversion rate of chromium in the reaction solution was detected by the method described in GB / T 1611-2003, and the conversion rate of chromium was 75.75% (the utilization rate of hydrogen was 63.66%). The product was subjected to solid-liquid separation, and the solid was hydrated chromium oxide. The calcined and cooled material is tested by the HG / T2775-1996 standard, and the chromium oxide content is 99.9...

Embodiment 3

[0051] Prepare 1000ml of sodium chromate solution with a concentration of 3.09mol / l to become the initial reaction solution, place it in a 3000ml reactor, and fill it with a hydrogen pressure of 6.8MP (about 131% of the theoretical hydrogen distribution). Control the heating voltage of 180v and the stirring speed of 400rpm to make the reaction system heat up and react. The maximum pressure of the system was 16.5MP, and the reaction was carried out at 350°C for 60 minutes to obtain a complete reaction solution, and then the temperature was naturally cooled to room temperature and discharged. The conversion rate of chromium in the reaction solution was detected by the method described in GB / T 1611-2003. The conversion rate of chromium was 90.36% (the utilization rate of hydrogen was 68.98%). The product was separated into solid and liquid, and the solid was hydrated chromium oxide. The calcined and cooled material is tested by the HG / T2775-1996 standard, and the chromium oxide c...

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Abstract

The invention provides a method for preparing chromic oxide. The method comprises the following steps of: introducing reduction gas containing hydrogen into a high-temperature high-voltage reaction kettle to perform a reduction reaction on alkali metal salt of chromic acid or dichromic acid which serves as a raw material; cooling and depressurizing a reacted solution; and performing solid-liquid separation to obtain hydrated chromium sesquioxide and corresponding caustic alkali solution. By the process method provided by the invention, the corresponding caustic alkali product and the hydrated chromium sesquioxide can be prepared at the same time, and series of chromic oxide products can be prepared by further modifying the hydrated chromium sesquioxide; and the high-temperature high-pressure reaction kettle is adopted as a reactor, the reaction efficiency can be improved, and self-heat reaction can be simultaneously implemented by utilizing system reaction heat to achieve the aims of saving energy and reducing carbon emission. No waste water, waste residues or waste gas is generated in the process of preparing the chromic oxide and caustic alkali products, so that high-efficiency, energy-saving and pollution-free production of the chromic oxide can be implemented.

Description

technical field [0001] The invention relates to a production method of chromium oxide, in particular to a method for producing chromium oxide by reducing chromate or dichromate with reducing gas under hydrothermal conditions, and simultaneously producing corresponding caustic alkali solution. Background technique [0002] Chromium oxide, also known as chromium trioxide, is mainly used in metallurgy, pigments, abrasives, refractory materials, melt-blown coatings, catalysts and their carriers. Chromium oxide for metallurgy accounts for the largest proportion, followed by green pigments, which are mainly used in coatings, inks, ceramics, enamel, colored cement and other products. Chromium oxide can reflect infrared light similarly to chlorophyll, and is used to formulate camouflage paint that resembles clusters of green leaves. As an abrasive, chromium oxide is mainly used for grinding and polishing of machinery, instruments, meters, clocks and ball bearings. Chromium oxide c...

Claims

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Application Information

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IPC IPC(8): C01G37/02
Inventor 梅海军王劲松宋卫国尹新建杨永飚王爱山张忠
Owner TIANJIN PAISEN TECH
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